This conceptual history traces the rise of "social capital" from the theories of James Coleman and Pierre Bourdieu to its eventual adoption in fields such as primatology and evolutionary psychology. It argues that the earliest theories of social capital were formulated in response to a growing perception that education was an economic investment. It argues, moreover, that peculiarities in the earliest theories of social capital, as well as a confluence of historical factors, led to an explosion of social capital research during the 1990s and 2000s. Though researchers have attributed social capital's meteoric rise to the expansion of neoliberal discourse, my account suggests that the factors behind the concept's growth were more complex and manifold. Social capital has never been a singular idea with clear ties to a single theory or ideology. It is all the more troubling, then, that many researchers have discussed this nebulous concept as if it were a self-explanatory and universal empirical principle that can be used to generate "further knowledge." Recommendations for mitigating this problem are made by discussing how researchers should (and should not) use terms such as social capital, neoliberalism, and analytic concepts in general.